An image forming apparatus including: a light source configured to emit a light beam based on an image signal; a deflector configured to deflect the light beam so that the light beam emitted from the light source is scanned on a surface of a photosensitive member in a main scanning direction; a storage portion configured to store a first magnification of an image with respect to a scanning position in the main scanning direction; and a controller configured to generate a second magnification of the image with respect to a reference color image, wherein the controller generates a third magnification based on the first magnification corrected based on the second magnification and the second magnification to correct the image signal based on the third magnification.

An image forming apparatus includes a photosensitive member; a scan unit configured to scan the photosensitive member with light based on image data, and form a latent image on the photosensitive member; a developing unit configured to form an image on the photosensitive member by attaching toner to the latent image formed on the photosensitive member; and a correction unit configured to correct an exposure amount of the photosensitive member such that a density change of the image in a main scanning direction due to a configuration of the scan unit and a density of the image to be formed is reduced.

An image forming apparatus includes an image forming unit configured to form an image on an image carrier using a developer, an image sensor configured to detect the image formed on the image carrier, and a correction controller configured to control the image forming unit to form an imaging correction pattern, and perform an imaging correction using a detection result of the image sensor detecting the image correction pattern. The correction controller is configured to control the image forming unit to form a first imaging correction pattern including a first number of one or more sub-patterns for an imaging correction until a predetermined condition is satisfied, and upon the predetermined condition being satisfied, form a second imaging correction pattern including a second number of sub-patterns more than the first number for a subsequent imaging correction.

An image forming apparatus includes a photosensitive drum; an exposure portion including light emitting elements; and a controller configured to control activation of the light emitting elements. The exposure portion includes array chips, each including the light emitting elements, a substrate on which the array chips are arranged in a staggered fashion in the rotational axis direction, and a substrate temperature detecting portion. The controller includes a correcting portion configured to correct magnification of the image data with respect to the rotational axis direction depending on a length fluctuation amount of the substrate calculated on the basis of the temperature detected by the temperature detecting portion, and a converting portion. Depending on magnification correction by the correcting portion, the image data is arranged by the converting portion on the basis of the mounting positions of the array chips.

If a timing of outputting magnification correction data for first image data to form first electrostatic latent image for an (n+1)th print medium overlaps a timing of outputting magnification correction data for second image data to form an electrostatic latent image for an nth print medium having a size smaller than the (n+1)th print medium in a conveyance direction of the print medium, a CPU outputs the magnification correction data for the second image data to form the second electrostatic latent image for the nth print medium before the magnification correction data for the first image data to form the first electrostatic latent image for the (n+1)th print medium is output and outputs the magnification correction data for the (n+1)th print medium after a magnification correction process performed by a second data processing unit based on the magnification correction data for the nth print medium is completed.

An information processing apparatus is configured to correctly detect a polygon face of a mirror being scanned even when noise occurs in a synchronization signal. The information processing apparatus is connected to an image forming apparatus including a laser light source configured to receive image data and output light; a photosensitive member; a polygon mirror, which has a plurality of reflection faces, and is configured to rotate to deflect a laser beam through use of the plurality of reflection faces, to thereby scan the photosensitive member; and a generator configured to generate a marking BD (beam detection) signal based on the deflected laser beam. The information processing apparatus receives a marking signal and determines whether or not the received marking signal is a signal corresponding to a specific reflection face among the reflection faces of the polygon mirror.

An image forming apparatus includes a photosensitive member; a scan unit configured to scan the photosensitive member with light based on image data, and form a latent image on the photosensitive member; a developing unit configured to form an image on the photosensitive member by attaching toner to the latent image formed on the photosensitive member; and a correction unit configured to correct an exposure amount of the photosensitive member such that a density change of the image in a main scanning direction due to a configuration of the scan unit and a density of the image to be formed is reduced.

An image forming apparatus includes a photosensitive drum; an exposure portion including light emitting elements; and a controller configured to control activation of the light emitting elements. The exposure portion includes array chips each including the light emitting elements, a substrate on which the array chips are arranged in a staggered fashion in the rotational axis direction, and a substrate temperature detecting portion. The controller includes a correcting portion configured to correct magnification of the image data with respect to the rotational axis direction depending on a length fluctuation amount of the substrate calculated on the basis of the temperature detected by the temperature detecting portion, and a converting portion. Depending on magnification correction by the correcting portion, the image data is arranged by the converting portion on the basis of the mounting positions of the array chips.

An image forming apparatus includes a photosensitive member; an exposure portion configured to expose the photosensitive member to light depending on image information to form a latent image on the photosensitive member; a developing portion configured to develop the latent image into a toner image with toner; and a transfer portion configured to transfer the toner image from the photosensitive member onto a recording material. The image forming apparatus changes a surface movement speed of the photosensitive member at timing prior to predetermined timing, when a moving speed of a recording material at the transfer portion changes, by a predetermined time.

An image forming apparatus includes a photosensitive member, a light source, a deflecting unit, a storing unit, a correcting unit, and a light source driving portion. Magnification correction data is determined using a quadratic function of a variable representing a scanning position with respect to a scanning direction. Coefficients of two quadratic functions corresponding to adjacent two regions included in a plurality of scanning regions are set so that a differential value calculated at the variable corresponding to a boundary of the two regions by a differential of the quadratic function for one region and a differential value calculated at the variable corresponding to the boundary of the two regions by a differential of the quadratic function for the other region are equal to each other.